Abstract: In the alkali/surfactant/polymer (ASP) flooding technology to enhance oil recovery, the unmatched alkali and polymer have serious influence on the study of composition of displacing system and application of ASP flooding. For the condition of Daqing oil field, the rheologic behavior of ASP solution has been systematically studied by using HAAK rheometer. The results show that the viscoelasticity of ASP solution decreases obviously with the addtion of alkali (see Fig.1). By using AFM, the effect of alkali on the molecular configuration of polymer has been studied. In obsence of alkali, polymer molecules stretch out themselves in liquid phase. But polymer molecules huddle up by adding alkali. The higher alkali concentration is the compacter curly clew of polymer molecules. With low alkali concentration (mass fraction 0.3％),polymer molecules cannot extent fully and exist in aggregation of multi-molecules(see Fig.5).

Key words: Alkali, Polymer, Molecule configuration, Rheologic behavior, 　Aggregation of multi-molecules